LOCATION ARAVAIPA                AZ

Established Series
Rev. SDH/DLR
05/2011

ARAVAIPA SERIES

The Aravaipa series consists of deep, well drained soils that formed in colluvium from granite. Aravaipa soils are on rolling hills and pediments and have slopes of 3 to 60 percent. The mean annual precipitation is about l6 inches and the mean annual air temperature is about 62 degrees F.

TAXONOMIC CLASS: Clayey-skeletal, mixed, superactive, thermic, shallow Aridic Argiustolls

TYPICAL PEDON: Aravaipa very gravelly loam-rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 1 inch; brown (10YR 5/3) very gravelly loam, dark brown (10YR 3/3) moist; weak medium platy structure parting to moderate fine granular; slightly hard, very friable, nonsticky and nonplastic; common very fine roots; many very fine and fine interstitial pores; 50 percent fine gravel; moderately acid (pH 6.0); abrupt smooth boundary. (1 to 2 inches thick)

Bt1--1 to 5 inches; brown (10YR 4/3) very gravelly clay loam, very dark grayish brown (10YR 3/2) moist; moderate fine subangular blocky structure; slightly hard, friable, very sticky and plastic; many very fine and fine roots; many very fine and fine interstitial and common very fine tubular pores; few thin clay films on faces of peds; 40 per cent fine gravel; neutral (pH 6.8); clear smooth boundary. (3 to 6 inches thick)

Bt2--5 to 13 inches; brown (10YR 4/3) very gravelly clay, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; slightly hard, friable, very sticky and very plastic; many very fine and fine roots; many very fine and fine tubular and interstitial pores; common thin clay films in pores and on faces of peds; 40 percent fine gravel; neutral (pH 7.0); abrupt smooth boundary. (7 to l2 inches thick)

Ct--13 to 45 inches; yellowish red (5YR 5/6) grus, yellowish red (5YR 4/6) moist; massive; extremely hard, but can be broken into fine and medium angular gravel; few very fine and fine roots; common very fine fractures; common moderately thick clay films in fractures; neutral (pH 6.8); clear smooth boundary. (22 to 45 inches thick)

R--45 inches; unweathered granite; extremely hard.

TYPE LOCATION: Graham County, Arizona; l,900 feet east and l,700 feet south of the NW corner of section 30, T. 7 S., R. 22 E.

RANGE IN CHARACTERISTICS:
Depth to strongly weathered granite (grus): 8 to 20 inches

Depth to consolidated granitic bedrock: 40 to 60 inches.

Rock fragments: 35 to 60 percent fine gravel by volume.

Mean annual soil temperature: 54 to 66 degrees F.

Soil moisture: Aridic ustic moisture regime

Organic matter: l to 3 percent

Soil reaction: slightly acid to mildly alkaline

A horizon
Hue: l0YR, 7.5YR
Value: 4 or 5 dry, 2 to 4 moist
Chroma: 2 or 3
Texture: loam, sandy clay loam, sandy loam, clay loam.

Bt horizon
Hue: l0YR or 7.5YR
Value: 3 or 4 dry, 2 to 5 moist
Chroma: 2 or 3 dry, 2 to 6 moist
Texture: clay, sandy clay, clay loam.

C horizon
Hue: varicolored l0YR through l0R, dominantly 5YR or 7.5YR
Value: 4 to 7 dry, 3 to 6 moist
Chroma: 2 to 6
This material is highly weathered granite (grus) that readily breaks down when wet to dominantly gravel-size particles. This material grades to consolidated bedrock at depths of 40 to 60 inches.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Aravaipa soils are on rolling granitic hills and pediments at elevations of 3,500 to 6,460 feet. Slopes range from 3 to 60 percent. These soils formed in granitic residuum. The climate is semiarid continental. The mean annual air temperature ranges from 57 to 69 degrees F., and the average annual precipitation ranges from l6 to 20 inches. The frost-free season ranges from l50 to 230 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Alsco, Comoro, Eloma, Lampshire, Santo Tomas, and Selevin soils. Alsco, Eloma and Selevin soils lack mollic epipedons and lack bedrock at a depth of less than 60 inches. Comoro and Santo Tomas soils lack argillic horizons and lack bedrock at a depth of less than 60 inches. Lampshire soils lack argillic horizons and have bedrock at a depth of less than 20 inches.

DRAINAGE AND PERMEABILITY: Well drained; medium runoff; slow permeability.

USE AND VEGETATION: These soils are used primarily for livestock grazing. Vegetation is scrub liveoak, juniper, wait-a-minute, and skunkbush, with an understory of sideoats grama, black grama, curly mesquite, threeawn, and cane beardgrass.

DISTRIBUTION AND EXTENT: Southeastern Arizona. The series is inextensive. MLRA 41 & 38.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona

SERIES ESTABLISHED: Gila-Duncan Area, Graham County, Arizona; 1979.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

Mollic epipedon - the zone from 0 to 13 inches. (A and Bt horizons)

Argillic horizon - the zone from 1 to 13 inches. (Bt horizons)

Lithic contact - the zone at 45 inches. (R horizon)

Classified according to Soil Taxonomy Second Edition, 1999; Keys to Soil Taxonomy Eleventh Edition, 2010.

Revised for the correlation of Graham County, AZ, Southwestern Part; March, 2011, WWJ

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National Cooperative Soil Survey
U.S.A.